1. Field of the Invention
This invention relates generally to atherectomy devices and more specifically to such devices with a housing having a rotating helical cutter.
2. Description of the Prior Art
One of the causes of heart disease is atherosclerosis. Atherosclerosis results when plaque builds up on the lining of the arteries. The term "plaque" refers to a number of different substances ranging from soft fat-like tissues to hard bone-like calcium deposits. Eventually, the plaque can completely block or occlude the artery and cause heart failure.
One way to treat atherosclerosis is a procedure known as an atherectomy. During an atherectomy, an incision is made in an artery and a catheter is threaded up through the artery to the position of the blockage. A tool for cutting or removing the blockage is located at the end of the catheter.
Some examples of various prior art atherectomy devices include the following: U.S. Pat. No. 4,732,154, issued to Shiber, on Mar. 22, 1988; U.S. Pat. No. 4,589,412, issued to Kensey, on May 20, 1986; U.S. Pat. No. 4,631,052, issued to Kensey, on Dec. 23, 1986; U.S. Pat. No. 4,669,469, issued to Gifford, III, et al., on Jun. 2, 1987; U.S. Pat. No. 4,690,140, issued to Mecca, on Sept. 1, 1987; U.S. Pat. No. 4,808,153, issued to Parisi, on Feb. 28, 1989; U.S. Pat. No. 4,020,847, issued to Clark, III, on May 3, 1977; U.S. Pat. No. 4,445,509, issued to Auth, on May 1, 1984; U.S. Pat. No. 4,771,774, issued to Simpson, et al, on Sept. 20, 1988; U.S. Pat. No. 4,749,376, issued to Kensey, et al, on Jun. 7, 1988; U.S. Pat. No. 4,765,332, issued to Fischell, et al, on Aug. 23, 1988; U.S. Pat. No. 4,784,636, issued to Rydell, on Nov. 15, 1988; U.S. Pat. No. 4,790,812, issued to Hawkins, Jr., et al, on Dec. 13, 1988; U.S. Pat. No. 4,790,813, issued to Kensey, on Dec. 13, 1988; U.S. Pat. No. 4,686,982, issued to Nash on Aug. 18, 1987; U.S. Pat. No. 4,729,763, issued to Henrie, on Mar. 8, 1988; U.S. Pat. No. 4,745,919, issued to Bundy, et al, on May 24, 1988; U.S. Pat. No. 4,728,319, issued to Masch, on Mar. 1, 1988; U.S. Pat. No. 4,696,667, issued to Masch, on Sept. 29, 1987; U.S. Pat. No. 4,621,636, issued to Fogarty, on Nov. 11, 1986; U.S. Pat. No. 4,273,128, and issued to Lary, on Jun. 16, 1981. The prior art also includes European patent application Publication No. 0163502A2, by Simpson and published on Apr. 12, 1985.
One problem with devices of the prior art is that they are long in length. This prevents their use in areas close to the heart because of the sharp turns in the arteries in that area. Another problem with the prior art devices is that they have trouble cutting away a flap-like piece of plaque. The flap of plaque moves as the cutting device advances and prevents the cutting device from getting a purchase or hold on the flap in order to cut it away. Another problem with the prior art devices is that they must be removed and repositioned several times during an operation in order to clean out the plaque collected. These devices typically have a small chamber to collect the plaque and this chamber must be emptied before it is full.